#include <stdio.h>
#include <stdlib.h>
#include "jpgfile.h"
#include "jpeglib.h"
#include <setjmp.h>
#include "psd_system.h"

typedef struct  
{
	struct jpeg_error_mgr pub;	/* "public" fields */

	jmp_buf setjmp_buffer;	/* for return to caller */
}my_error_mgr;


/*
 * Here's the routine that will replace the standard error_exit method:
 */

METHODDEF(void)
my_error_exit (j_common_ptr cinfo)
{
  /* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
  my_error_mgr* myerr = (my_error_mgr *) cinfo->err;

  /* Always display the message. */
  /* We could postpone this until after returning, if we chose. */
  (*cinfo->err->output_message) (cinfo);

  /* Return control to the setjmp point */
  longjmp(myerr->setjmp_buffer, 1);
}

static void putRGBScanline(unsigned char *jpegline, int widthPix, unsigned char *outBuf, int row)
{
	int offset = row * widthPix * 3;
	int count;
	
	for (count=0;count<widthPix;count++) 
	{
		unsigned char iRed, iBlu, iGrn;
		unsigned char * oRed, *oBlu, *oGrn;

		iRed = *(jpegline + count * 3 + 0);
		iGrn = *(jpegline + count * 3 + 1);
		iBlu = *(jpegline + count * 3 + 2);

		oRed = outBuf + offset + count * 3 + 0;
		oGrn = outBuf + offset + count * 3 + 1;
		oBlu = outBuf + offset + count * 3 + 2;

		*oRed = iRed;
		*oGrn = iGrn;
		*oBlu = iBlu;
	}
}

static void putGrayScanlineToRGB(unsigned char *jpegline, int widthPix, unsigned char *outBuf, int row)
{
	int offset = row * widthPix * 3;
	int count;

	for (count=0;count<widthPix;count++) 
	{
		unsigned char iGray;
		unsigned char * oRed, *oBlu, *oGrn;

		// get our grayscale value
		iGray = *(jpegline + count);

		oRed = outBuf + offset + count * 3;
		oGrn = outBuf + offset + count * 3 + 1;
		oBlu = outBuf + offset + count * 3 + 2;

		*oRed = iGray;
		*oGrn = iGray;
		*oBlu = iGray;
	}
}




int jpg_save(char * filename,unsigned char *image_buffer,int image_width,int image_height,int quality)
{
  struct jpeg_compress_struct cinfo;
  struct jpeg_error_mgr jerr;
  /* More stuff */
  FILE * outfile;		/* target file */
  JSAMPROW row_pointer[1];	/* pointer to JSAMPLE row[s] */
  int row_stride;		/* physical row width in image buffer */

  /* Step 1: allocate and initialize JPEG compression object */

  /* We have to set up the error handler first, in case the initialization
   * step fails.  (Unlikely, but it could happen if you are out of memory.)
   * This routine fills in the contents of struct jerr, and returns jerr's
   * address which we place into the link field in cinfo.
   */
  cinfo.err = jpeg_std_error(&jerr);
  
  /* Now we can initialize the JPEG compression object. */
  jpeg_create_compress(&cinfo);

  /* Step 2: specify data destination (eg, a file) */
  /* Note: steps 2 and 3 can be done in either order. */

  /* Here we use the library-supplied code to send compressed data to a
   * stdio stream.  You can also write your own code to do something else.
   * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
   * requires it in order to write binary files.
   */
  if ((outfile = fopen(filename, "wb")) == NULL) {
    fprintf(stderr, "can't open %s\n", filename);
    return -1;
  }
  jpeg_stdio_dest(&cinfo, outfile);

  /* Step 3: set parameters for compression */

  /* First we supply a description of the input image.
   * Four fields of the cinfo struct must be filled in:
   */
  cinfo.image_width = image_width; 	/* image width and height, in pixels */
  cinfo.image_height = image_height;
  cinfo.input_components = 3;		/* # of color components per pixel */
  cinfo.in_color_space = JCS_RGB; 	/* colorspace of input image */
  /* Now use the library's routine to set default compression parameters.
   * (You must set at least cinfo.in_color_space before calling this,
   * since the defaults depend on the source color space.)
   */
  jpeg_set_defaults(&cinfo);
  /* Now you can set any non-default parameters you wish to.
   * Here we just illustrate the use of quality (quantization table) scaling:
   */
  jpeg_set_quality(&cinfo, quality, TRUE /* limit to baseline-JPEG values */);

  /* Step 4: Start compressor */

  /* TRUE ensures that we will write a complete interchange-JPEG file.
   * Pass TRUE unless you are very sure of what you're doing.
   */
  jpeg_start_compress(&cinfo, TRUE);

  /* Step 5: while (scan lines remain to be written) */
  /*           jpeg_write_scanlines(...); */

  /* Here we use the library's state variable cinfo.next_scanline as the
   * loop counter, so that we don't have to keep track ourselves.
   * To keep things simple, we pass one scanline per call; you can pass
   * more if you wish, though.
   */
  row_stride = image_width * 3;	/* JSAMPLEs per row in image_buffer */

  while (cinfo.next_scanline < cinfo.image_height) {
    /* jpeg_write_scanlines expects an array of pointers to scanlines.
     * Here the array is only one element long, but you could pass
     * more than one scanline at a time if that's more convenient.
     */
    row_pointer[0] = & image_buffer[cinfo.next_scanline * row_stride];
    (void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
  }

  /* Step 6: Finish compression */

  jpeg_finish_compress(&cinfo);
  /* After finish_compress, we can close the output file. */
  fclose(outfile);

  /* Step 7: release JPEG compression object */

  /* This is an important step since it will release a good deal of memory. */
  jpeg_destroy_compress(&cinfo);

  /* And we're done! */
  return 0;
}


unsigned char *jpg_load(char *fileName,unsigned int *width,unsigned int *height)
{
	unsigned char *dataBuf;
	
	/* This struct contains the JPEG decompression parameters and pointers to
	* working space (which is allocated as needed by the JPEG library).
	*/
	struct jpeg_decompress_struct cinfo;
	/* We use our private extension JPEG error handler.
	* Note that this struct must live as long as the main JPEG parameter
	* struct, to avoid dangling-pointer problems.
	*/
	my_error_mgr jerr;
	/* More stuff */
	FILE * infile=NULL;		/* source file */

	JSAMPARRAY buffer;		/* Output row buffer */
	int row_stride;		/* physical row width in output buffer */
	char buf[250];

	/* In this example we want to open the input file before doing anything else,
	* so that the setjmp() error recovery below can assume the file is open.
	* VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
	* requires it in order to read binary files.
	*/
	  /* We set up the normal JPEG error routines, then override error_exit. */
	  cinfo.err = jpeg_std_error(&jerr.pub);
	  jerr.pub.error_exit = my_error_exit;
	  /* Establish the setjmp return context for my_error_exit to use. */
	  if (setjmp(jerr.setjmp_buffer)) {
	    /* If we get here, the JPEG code has signaled an error.
	     * We need to clean up the JPEG object, close the input file, and return.
	     */
	    jpeg_destroy_decompress(&cinfo);
	    fclose(infile);
	    return 0;
	  }

	if ((infile = fopen(fileName, "rb")) == NULL) {
		sprintf(buf, "JPEG :\nCan't open %s\n", fileName);
		return NULL;
	}

	/* Step 1: allocate and initialize JPEG decompression object */
	cinfo.err = jpeg_std_error(&jerr);

	/* Now we can initialize the JPEG decompression object. */
	jpeg_create_decompress(&cinfo);

	/* Step 2: specify data source (eg, a file) */

	jpeg_stdio_src(&cinfo, infile);

	/* Step 3: read file parameters with jpeg_read_header() */

	(void) jpeg_read_header(&cinfo, TRUE);
	/* We can ignore the return value from jpeg_read_header since
	*   (a) suspension is not possible with the stdio data source, and
	*   (b) we passed TRUE to reject a tables-only JPEG file as an error.
	* See libjpeg.doc for more info.
	*/

	/* Step 4: set parameters for decompression */

	/* In this example, we don't need to change any of the defaults set by
	* jpeg_read_header(), so we do nothing here.
	*/

	/* Step 5: Start decompressor */

	(void) jpeg_start_decompress(&cinfo);
	/* We can ignore the return value since suspension is not possible
	* with the stdio data source.
	*/

	/* We may need to do some setup of our own at this point before reading
	* the data.  After jpeg_start_decompress() we have the correct scaled
	* output image dimensions available, as well as the output colormap
	* if we asked for color quantization.
	* In this example, we need to make an output work buffer of the right size.
	*/ 

	////////////////////////////////////////////////////////////
	// alloc and open our new buffer
	dataBuf = psd_malloc(cinfo.output_width*cinfo.output_height*3);
	if (dataBuf==NULL) 
	{
		jpeg_destroy_decompress(&cinfo);
		fclose(infile);
		return NULL;
	}

	/* JSAMPLEs per row in output buffer */
	row_stride = cinfo.output_width * cinfo.output_components;

	/* Make a one-row-high sample array that will go away when done with image */
	buffer = (*cinfo.mem->alloc_sarray)
		((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);

	/* Step 6: while (scan lines remain to be read) */
	/*           jpeg_read_scanlines(...); */

	/* Here we use the library's state variable cinfo.output_scanline as the
	* loop counter, so that we don't have to keep track ourselves.
	*/
	while (cinfo.output_scanline < cinfo.output_height) {
		/* jpeg_read_scanlines expects an array of pointers to scanlines.
		 * Here the array is only one element long, but you could ask for
		 * more than one scanline at a time if that's more convenient.
		 */
		(void) jpeg_read_scanlines(&cinfo, buffer, 1);
		/* Assume put_scanline_someplace wants a pointer and sample count. */

		// asuumer all 3-components are RGBs
		if (cinfo.out_color_components==3) {
			putRGBScanline(buffer[0],cinfo.output_width,dataBuf,cinfo.output_scanline-1);
		} else if (cinfo.out_color_components==1) {
			// assume all single component images are grayscale
			putGrayScanlineToRGB(buffer[0], cinfo.output_width,dataBuf,cinfo.output_scanline-1);
		}

	}

	/* Step 7: Finish decompression */

	(void) jpeg_finish_decompress(&cinfo);
	/* We can ignore the return value since suspension is not possible
	* with the stdio data source.
	*/

	/* Step 8: Release JPEG decompression object */

	/* This is an important step since it will release a good deal of memory. */
	jpeg_destroy_decompress(&cinfo);

	/* After finish_decompress, we can close the input file.
	* Here we postpone it until after no more JPEG errors are possible,
	* so as to simplify the setjmp error logic above.  (Actually, I don't
	* think that jpeg_destroy can do an error exit, but why assume anything...)
	*/
	fclose(infile);

	/* At this point you may want to check to see whether any corrupt-data
	* warnings occurred (test whether jerr.pub.num_warnings is nonzero).
	*/

	// how big is this thing gonna be
	if (width)
		*width = cinfo.output_width;
	if (height)
		*height = cinfo.output_height;
	
	return dataBuf;
}

